A guiding light for decision makers

The Natural Step (TNS), an international charity promoting sustainable development through the use of science, has produced a guide helping decision-makers link the Life Cycle Assessment (LCA) of products, processes and activities to the broader context of sustainable development. In this article, Dr Mark Everard, director of science at The Natural Step, outlines some of the principles covered by the guide.


Sustainable development is an ever more urgent issue that society must address, and there is a need to use good science to guide decision-making. Life Cycle Assessment (LCA) is a widely-established tool for exploring the environmental impacts of defined life cycles of products, processes and activities. It is undoubtedly helpful in informing decision-making by quantifying these impacts. However, whilst a useful management tool for closely-defined purposes, LCA does not automatically guide more sustainable decision-making.

The guide, entitled Life Cycle Assessment and Sustainability: Adding Value with The Natural Step Framework, aims to help those grappling with sustainability issues across product or process life cycles, and to inform decision-making by connecting the analytical power of LCA with the broader context of sustainable development.

The pace of change in our fast-moving world is accelerating, and nowhere faster than in business. Although the pressures that enforce these changes are diverse, many stem from the squeeze between diminishing resources, rising global population and material expectations. The Natural Step (TNS) uses the metaphor of the ‘funnel’ to describe how these pressures impinge increasingly upon the ‘license-to-operate’ granted to businesses by society.

As one approaches the funnel’s walls, sustainability-related pressures manifest in ways as diverse as economic signals (recent examples include the UK’s Aggregates and Landfill Taxes), reputation issues heightened by media interest, more stringent emission regulations, health and safety liabilities, increasing difficulties obtaining capital or planning permission, etc.

There is no reliable method for determining by which route these pressures will impinge upon the activities of a business or other organisation. Indeed, sustainability pressures have a habit of manifesting in unpredictable ways. For example, the PR furore over PVC in recent years, the discovery of the endocrine-disrupting properties of a range of compounds, and impacts on resource availability arising from conflicts in productive areas of the world, were all largely unforeseeable.

Over-emphasis of just some facets of the environmental impacts of products and processes may therefore prepare one poorly for the inevitably changing world in which we live. Social and economic factors are obviously of major significance, but so too are environmental implications connected with all parts of the ‘life cycle’, including sources of raw materials and fate of substances post-disposal. For this, TNS believes that the only sensible context for exploring the sustainability challenges of a product or process is the sustainability principles governing the workings of the natural world and human interactions with it.

Key strengths

The key strength that LCA offers is the assessment in quantitative terms of the relative environmental impacts of materials, processes, technologies or products, and their alternatives, in specific applications. It achieves this by using a science-based systems approach to addressing inputs and outputs. This quantification is helpful in providing hard guidance on options, based upon fact rather than perception or guesswork. Within the selected ‘life cycle’ boundaries, LCA provides a valuable mechanism for quantitative options appraisal, and for screening. There is however a lack of prescription about those ‘life cycle’ boundaries within LCA, which are instead left for the user to define.

To believe that the impacts of a process or product stop at a largely arbitrary point of ‘disposal’ is naive. The very term ‘cradle to grave’, which features in the ISO14040 standard definition of LCA, implies a linear process from source to waste, at odds with the sustainable supportive cycles of this planet. The term ‘cradle to cradle’ would fit better with this cyclic concept of sustainability, as nothing simply ‘disappears’ in nature. All resources, be they natural products or wastes, remain subject to the natural cycles operating on this planet. Sustainability considerations must apply to the complete natural cycle of materials and not merely the human-defined segment of their journey through the economy.

Sustainable development

There is no automatic ‘navigation’ with respect to sustainability principles within LCA applied in isolation, and neither is the intent of LCA to cover the full ‘triple bottom line’ of environmental, economic and social issues that constitute sustainability thinking. Numerous attempts have been made to expand the application of LCA to take account of these wider dimensions of sustainable development (for example, the 2001 DETR report Life Cycle Assessment of Polyvinyl Chloride and Alternatives). However, all seem to demonstrate the shortcomings of ‘bolting on’ social and economic elements to a tool not implicitly attuned to strategic sustainable development assessment. The focus of LCA is tight and environmental, and it is therefore best deployed for discrete purposes within an overall framework of sustainability.

Since both the principles of sustainability of TNS and the LCA tool utilise an objective basis in science, and both are based on systems analysis, there is a logical fit between the strategic overview provided by TNS principles and the specific quantification provided by LCA. The former provide qualitative ‘navigation’ with respect to the journey of sustainable development – the latter provides quantified metrics with respect to specific environmental issues. This linkage of context and tool is indeed implicit in the intent of LCA as the ISO 14040 standard notes that, in interpreting LCA outputs: “Generally, the information developed in an LCA study should be used as part of a much more comprehensive decision process…”

The environmental focus of LCA is not therefore a weakness. But we need to be aware that the environmental elements addressed by LCA are only a part of the sustainability story, and that this story has to be addressed within a cohesive framework of understanding of sustainability. The user is free to determine the system boundaries in an LCA, and for a true sustainability assessment the biosphere of this planet (the basis for TNS principles) defines the finite limits of ‘carrying capacity’.

This must necessarily force us to consider the life cycle beyond ‘end-of-life’ of products or after disposal. After all, burying or burning does not make things ‘disappear’ from the earth system, and the capacity for harmful effects upon life-support systems is not inhibited over anything other than the most parochial of human time scales.

Furthermore, linear use is wasteful, as no further beneficial use of the resource occurs post-disposal. This can reinforce existing inequities in the way that resources are shared across society.

Life cycle

Reframing the ‘life cycle’ within the broader context of the cyclic life-support systems of this planet, which make life and economic activities possible, is the logical context for sustainability. As a related TNS study (Towards the Sustainable Use of Material Resources) demonstrates, this creates different perspectives on sustainable use of materials, and an associated set of new economic opportunities arising from more cyclic use and a decreasing dependence on linear use.

If it is true that a well-quantified LCA without a broader sustainability context will not lead to more sustainable decision-making, it is also true that a vision of sustainability without the tools to make objective evaluation of options is lacking in pragmatism. There is therefore a close fit between the distinct roles of sustainability assessment (for example using TNS principles) and LCA. The TNS guide Life Cycle Assessment and Sustainable Development: Adding Value with The Natural Step Framework provides practical guidance to help managers and practitioners address that linkage. Though laid out in more detail in the report, the steps identified are summarised below.

It is firstly recommended that a full qualitative sustainability evaluation be conducted prior to the expensive and data-heavy quantitative evaluation of LCA. This sets the broader context of environmental, social and economic factors germane to sustainable decision-making. It ensures that LCA can be focused on key questions relative to the flows of resources that are critical to sustainability, provides a common framework for comparison of other products and processes subject to LCA, and also helps ensure that LCAs are conducted in a more targeted, cost-effective and efficient way. An example of one such influential sustainability evaluation is PVC: An Evaluation Using The Natural Step Framework.

ISO standards

Having identified the key environmental questions that the LCA should be addressing, and the context within which outputs should be interpreted, the LCA itself can then proceed along largely traditional lines, consistent with the ISO standards. The choice of metrics can then be tailored to the desired goal of the LCA, and the need for comparison between LCAs. A word of caution though. Whilst a number of ‘off-the-shelf’ tools for LCA are available from proprietary sources, but it should not be assumed that the settings and parameters within these tools are automatically appropriate for a sustainability-based LCA.

Interpretation of outcomes from LCA studies must then be within the sustainability context identified through the qualitative sustainability evaluation. Appraisal of strategic choices or options is thereby automatically more closely related to incremental steps towards the end-goal of sustainability. Without that context, remember, ‘eco-efficient unsustainability’ remains a real risk! All of this is consistent with ISO14040 which specifies that, “There is no single method for conducting LCA studies. Organisations should have flexibility to implement LCA practically as established in this International Standard, based upon the specific application and the requirements of the user.”

Making decisions about trade-offs can be done with greater rigour by setting the LCA within the context of sustainability. For example, to use a now-historic example, are the ozone-depleting effects of CFCs refrigerants worse than the global-warming effects of HCFCs? In the absence of a broader sustainability evaluation, the tendency will be to explore trade-offs across the life cycle (with or without LCA) of these two fundamentally unsustainable refrigerants.

By contrast, a longer-term perspective may help resolve difficulties by helping identify innovations that result in no trade-off. For example, pioneering work by Electrolux in Sweden in 1994, using TNS principles, helped the company get themselves out of the CFC/HCFC dilemma by identifying butane/pentane refrigerants as a safer and ultimately more sustainable alternative that could be processed by natural cycles without adverse effects.

The science-based approach to sustainable development advanced by TNS provides an invaluable and robust context in which to plan for sustainability. Without such a framework, there is a real risk that LCA will inform about eco-efficiency without addressing fundamental principles of sustainability. As a rule: ‘LCA may help explore the life cycle of a product, but only a full sustainability evaluation will help develop a cyclic life’. The LCA tool and the ‘navigation’ provided by sustainability evaluation add substantial value to each other, and can represent an efficient use of resources since LCA can be an expensive exercise. You need to be confident that you are assessing the right things.


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